Method of and means for controlling prime-mover dynamo plants



June 3, 1930. A. PFAU 1,761,797

METHOD OF AND MEANS FOR CONTROLLING PRIME MOVER DYNAMO PLANTS v OriginalFiled Sept 11, 1924 Patented June 3, 1930 ARNOLD 'PFAU, OF MILWAUKEE,WISCONSIN, ASSIGNOR TO ALLIS CHALME-RS MANU- FACTURING COMPANY, OFMILWAUKEE, WISCONSIN, A CORPORATION OF DELA- WARE METHOD OF AND MEANSFOR CONTROLLING PRIME-MOVER- DYNAMO TS Original application filedSeptember 11, 1924, Serial No. 737,021. Divided and. this applicationfiled J'anumy 14, 1928. Serial No. 246,663.

This invention relates to a method of and means for controllmg a primemover drivmg a dynamo electr1c machine. The mvention relates moreparticularly to installations;

5 where the prime mover drives an alternating current generator andwhere it is desired tosynchronize the generator and bring it into phasewith the line to which it is to be connected.

'The broader aspects of the invention irrespective of the nature of thedevice driven by the prime mover are claimed in applicants copendingapplication S. 737,021, filed September 11, 1924 of which the presentappli- 15 cation is a divislon.

Undercertain conditions'it is difiicult to bring a prime mover tosynchronous speed with the line to which the generator driven by theprime mover is to be connected. A certain amount of fly wheel eflect isgenerally desirable for the reason thatif the prime mover is controlledby means of a governor and started in the usual manner it may occur thatthe governor will hunt at friction load.

The governor may hunt to such an extent that the speed cannot be heldsteady enough to permit the generator to be thrownin parallel with theline. The hunting may be so. severe that the means for admittingoperating fluid 30 to the prime mover may actually alternately open andclose. Complicated pipe line conditions, where the prime mover is, forexample, a hydraulic turbine, may also cause hunting when it isattempted to start the turbme under the control of the governor. Theseconditions may be remedied to s the provision of sufficient fly this isan expensive proce re.

- It is an object of this i vention to provid a method and means wherebythe hereinbefore mentioned difficulties may be overcome; and morespecifically whereby hunting of the governor during the starting andsynchronizing operation will be prevented irrespective of the amount offly wheel effect; and whereby prime mover and generator units providingonly a very small fly wheel effect not sufficient to enable the unit tobe started in the ordinary manner under the control of its governorwithout prohibitive hunting may be built and successfully started andsynchronized-under the control of a governor.

Still another object is the provision of a method and means forcontrolling a prime mover so that the power which may be suppliedthereby may be limited to a predetermined amount and whereby the load onthe system supplied by the primemover must fall to a predeterminedamount before the power supplied by said prime mover will be decreased,and whereby the said limits may be adjusted from a distant point.

A further object is the provision of a system in which a prime moverdriving an alternating current generator adapted to supply adistribution system may be started from rest and brought to synchronousspeed with said system,.the generator connected, and caused to assume aload under the control of a. governor, and in which all. theseoperations may be controlled by a single operator. More speciflcally, tothis end it is an object to provide a system which includes remotelycontrollable means for positively predetermining the maximum opening ofthe means for admitting operating fluid to the prime mover whereby, 'hesaid opening may be gradually permitted to increase as desired. Also, sothat the prime mover maybe caused, from-a distant point, to take a load,and the power furnished by said prime mover may at all times be limitedas desired.

Other objects will appear hereinafter as the description of theinvention proceeds.

The novel features of this invention will appear from this specificationand the accompanying drawing which forms a part thereof and shows oneembodiment of said 1nvention andv all these novel features are intendedto be pointed out in the claim.

The single figure of the drawing is a more or less diagrammatic showingof the inven tion as it may be applied in connection with a hydraulicturbine current generator and controlled by' a governor.

Referring to the drawing; the hydraulic turbine 1 is adapted to drive agenerator 2 through a shaft 3. The generator 2 may be connected by meansof any suitable switch 4 which may of course be electromagneticallyoperated if desired, to a distribution system or line 5 hre shown as ofthe three-phase t pe.

In order that the switch 4 may be closed when the generator 2 is runningsynchronously with the system 5 and is in phase therewith and at thesame voltage, various instruments may be provided such as thesynchroscope S and the volt meters V. y The synchroscope is here shownas fed by two spectively. The regulating valve is also Eroich' thecontrolof the v p ovided with a potential transformers 6, 7 connectedrespectively to be influenced by the distribution system 5 and by thegenerator 2. f One of the volt meters is connectedto transformer 6 toindicate line 'voltage and the other to transformer 7 to indicategenerator voltage.

. In order that the amount of current delivered by generator 2 to line 5may be indicated an. ammeter A may be provided. Watt meters (not shown)may of course also be provided. All of these instruments including theswitch 4 are preferably mounted within the operating scope ofa singleoperator. If the switch 4 is remotely controlled, only the mastercontrol switch therefor need of course be mounted near the otherinstruments. The turbine 1 is here shown as controlled by means of agate 8 disposed in the conduit.

adapted to admit water to the turbine. It is of course to be understoodthat any other means for controlling the admission of operating fluid tothe turbine may be prow'ded, such as for example, the usual guide vanes.The gate 8 ma be swung by'means of 'a crank 9 connected t rough a rod 10to the piston rod 11, of any suitable form of servo-motor. Theservo-motor is here shown as including a pair of pistons 12, 13operating in cylinders 14, 15 respectively. The servo-motor may becontrolled by means of a regulating valve 16 here shown as includingpiston valves 17 18'which are so spaced that they are respectivelyadapted to cover the ports of a pair of pipes19, 20. The pipes 19, 20,lead from the cylinder of valve 16 to cylinders 14, 15 revided withaninlet pipe 21 through w fluid under pressure may be admitted under sevo-motor. The regulating valve is also 7 pair of drain pipes 22, 23.

The pistons 17, 18 of the regulating valve maybe mounted on and operatedby means driving an alternating regulating valve to theof a rod or stem24 the upper end of which passes freely through a swivel nut.25pivotally mounted on a floating lever 26. The end of rod 24 is threadedto receive an adjustable nut 27 -:'against which the swivel nut 25 isadapted to abut. The rod 24 is provided 34, provided at the upperendwith a stop collar 77, is adapted to screw. The piston rod 34 isassociated with a piston anddash pot of a compensating device 35 of anyusual or desired form. The dash pot of the compensating device may beraised and lowered by means of a bell crank 36, 37 swingable about apivot 38. The arm 36 of the bell crank is connected by means of a link39 to v a crank 40 operating in unison with the crank 9 or gate 8. Thepiston rod 34 is here shown as provided with a gear 41 adapted to bedriven by a pinion 42 rotatable about a shaft 43. The shaft 43 may befixed in any suitable manner to a bracket 44 mounted on the dash pot 35.A worm wheel 45 is provided for driving the pinion 42 and said wormwheel is operable by means of a worm 46 driven in any suitable manner bya motor 48 as through a belt and pulley 47. The motor 48 is here shownas mounted on the bracket 44. The armature of-motor 48' is fed throughleads 49-oofinectible to buses 52 through a reversing switch 51. Thespeed of motor 48 may be controlled by means of a rheostat 50.

The field of motor 48 is fed from buses 52 through leads 53.

The governor may be robbed of its control of the regulating valve 16, toan extent hereinafter set forth, by means of a control finger 55swingable about a pivot 57. v The control finger 55 is, in the instanceshown,"adapted when swung in a counter-clockwise direction, to engage aprojection 56 associated in any suitable manner and at any desired pointwith the rod 24. The control finger 55 may be'swun by means of a lever58 operating in unison t -erew ith and forked at one end to receive aswivel nut 59. A motor 61 is here shown as mounted on the swivel nut 59as by means of a bracket 60. The motor 61 is adapted, through a-worm 62connected therewith, todrivea worm wheel 63 keyed to a shaft 64 freelyrotatable in the swivel nut 59. The shaft 64 is held in the swivel nut59 by means of a nut 65 on the upper threaded end of shaft 64.-Operatively associated threaded spindle 66 adapted to screw in or outof the threaded pipe 67. The -lower end of pipe 67 is adapted to slideover a rod 70 and in the position shown abuts against a clamp 68fastened, by means of the adjusting screw 69, to the rod 70. Theabutment constituted by the clamp 68 is made adjustable so that theposition of the control finger 55 may be adjusted irrespective of therelative positions of spindle 66 and pipe 67., This adjustability ishowever not necessarily essential. The rod 70 is pivoted at 71 to thearm 37 of bell crank 36, 37. In order to prevent turning of pipe 67 withrespect to rod 70, the rod 70 may be provided with a pin 72 engaging ina slot 73 formed in, the pipe 67.

, The armature of motor 61 is fed through lead 74 from buses 52 througha reversing switch 7 6. The speed of the motor 61 may be controlled by arheostat 75. The field of motor 61 is here shown as also fed throughleads 53. It is to be understood that the particular form of the motors48, 61 is not material. These motors might, for example, be of the splitfield reversing type and controlled in the manner customary with suchmotors.

' nection. The motor 61 may, if desired, be

The motors 48, 61 may, if desired be provided with limit switches toprevent them from over-running, or mechanical stops may be provided forthe same purpose in which case slip clutches or connections aredesirable. In

the instance shown, the belt connecting motor 48 with pulley 47 willserve as a slip consimilarly connected to the worm 62. It is to beunderstood that the connections between the motors 48, 61 and theirdriven members are merely by way of illustration.

The reversing switches 51, 76 and the rheostats 50, 75, or othercontrolling means for the motors 48, 61 are preferably located near thecontrolling means for switch 4 and the other instruments such as thesynchroscope, etc. 4

If desired the position of the spindle66 of the control finger may beindicated at a distant point, preferably at the location of the othercontrol instruments hereinbefore described. The same is true as to theposition of the nut 33. Inasmuch as indicating means ,7 for the purposeof showing thev position of members at a distant point are old and wellknown in the art none has been shownon the drawing.

The operation of the system is as follows. The parts are shown in thedrawing in the positions which they occupy when the turbine 1 is atrest, the gate 8 being closed. The

nut 33 is preferably positioned so that when the turbine and generatorhave been brought to synchronous speed with the line 5 and the generatorconnected, the generator will either float on the line or will deliver a'predeter mined amount of power thereto. when the governor is free toact. If now the operator desires to start the unit he closes the switch54 and closes the reversing switch 76in the proper direction so that themotor 61 will rotate in such av direction as to screw the spindle 66into the tube 67 thereby causing the control finger 55 to move in aclockwise direction at a speed dependent upon the adopen. Fluid underpressure will therefore be admitted through the regulating valve tocylinder 15 thereby moving the gate 8 to ward open position. Movement ofate 8 toward gate open position is relayed to control finger 55 by link39 swinging bell crank 36, 37 in a counter-clockwise direction therebycausing rod 7 0, by means fclamp 68, to push spindle 66 and thereforecontrol finger 55 in a counter-clockwise direction. This will causemovement of the regulating valve toward its neutral position in whichboth of the ports 19, 20 are closed thereby immediately stopping furtheradmission of fiuid' to cylinder 15 and further gate opening movement. Itwill be. evident that the clockwise movement of finger 55 caused bymotor 61 and the relay movement caused by the opening of the gate 8 willtake place substantially simultaneously so that the resultant effectwill be the openingof gate 8 at a predetermined rate under the positivecontrol of the finger 55. ,In' other words, it is impossible for theregulating valve 16 to act to cause opening of gate 8 to an amountgreater than that predetermined by the position of control finger 55 atany given instant. When the turbine has reached a speed synchronous withthat of the line 5 the nut 27 and the swivel nut 25 will be fairly closeto each other or in contact, depending upon the adjustment of the nut33. Further increase in speed, if it occurs, would cause the fly balls31 to lift the floating lever 26 swinging the sameiabout the pivot ofnut '33 thereby lifting the regulating valve stem 24 to the gateclosedposition and admitting fluid to cylinder'14. As soon as gate 8 begins tomove toward closed position, however, this motion movement of gate 8toward closed position has been more than necessary this will bereflected in a drop in speed and-consequent movement of the floatinglever to move the clear that these actions will valve 16 towardgate-open position.

movement of the gate, however, position will cause the control Anytoward open finger to return the valve 16 to neutral position and theity of voltages the operator may cause the on the-system which is beingfed dro determined substantial amount. Thls would, a

closure of switch 4 thereby placing the generator and line in parallel.If the nut 33 has been so set that the generator will take a load whenthe governoris freed of the control of finger 55 a predetermined amount,the op-- erator will reenergize motor 61' to cause the finger 55 toswing a predetermined amount further in a clockwise direction therebypermitting gate 8'to open further so that the generator may take -aload. The operator then, of course, stops the motor 61. At this time theunit is in normal running condition and the governor parts are in such aposition that the nut 27 isclose to or rests upon the swivel nut 25 andthe regulating valve 16 is in its neutral position.

If a larger load comes on the system 5, when the generator is operatingas hereinabove described, the fly balls 31 will lower the floating pivot30 thereby causing compressionof spring 29 for the reason that thecontrol finger 55 prevents the m vement of the regulating valve togate-open position.- It is therefore evident that the setting of thecontrol finger- 55 limits the amount of power that the turbine ispermitted to deliver and that the setting of this amount may becontrolled at any desired distance fromithe tur-v bine and governor.

It sometimes becomes desirable to cause a generating unit to deliver notmore than a predetermined amount. of power and also to preventtheggovernor from cutting back the amount of power delivered unless theload s a pre for example,'be true if the system 5 was fed bysteam-turbine-driven alternators and by the hydro-electric unit 1,.2.Usually a certain amount of water is avilable for the continuousproduction of powr d it is not desired to exceed the res tantdrain onthe water supply and yet I the same time it is highly advantageousparticularly for the f party selling the water power that the amount ofwater used be at alltimes near the maximum permissible limit. This isalso desirable from the viewp'gint of the saving of coal, where, asstated, th steamand hydraulic checked and the speed may units feed thesame system. If the hydroelectric unit may be caused to maintain theamount of power delivered thereby when a predetermined load is removedfrom the system, thereby permitting that load to be taken off of thesteam turbines rather than off of the hydraulic turbine, it is obviousthat coal will be saved. This result may be brou ht about by operatingthe motor 48 in such a direction, under the control of reversing vswitch51 and rheostat 50, that the gear 41 revolves in such a direction thatthe nut 33 will be raised-by the screwthreaded piston rod 34. With thecontrol finger 55 and the floating pivot 30 remaining in the sameposition thls will cause the swivel nut 25 to move away from the nut 27thereby compressing spring 29. When the desired movement of the nut 33has taken place the operator again stops motor 48. It will be evidentthat when the position of the parts has been thus changed, removal of apredetermined amount of load from system 5 will cause a predeterminedrise in speed of the unit and the fly balls will therefore moveoutwardly thereby raising the fioating pivot 30. The floating lever 26will rotate about the pivot of nut '33 and the nut 25 will be raised apredetermined amount dependin on what the rise in speed has been. It isfurthermore evident that unless this speed rise has been enough to causethe nut 25 to come in contact with nut 27 to thereby lift the regulatingvalve stem to the gate-closed position, the turbine gate will not bemoved toward closed osition but will remain where it was before t ehereinbefore described adjustment of nut 33. The turbine will thereforecontinue to supply the same amount of power to thesystem 5 as before thepredetermined load had been removed from that system. Other unitsfeeding the system are thereby relieved of that skilled in the art.

It is claimed and desired to secure by Letters Patent:

The method ef starting from rest, bringing to synchronous speed with adistribution sys tem, and causing a prime mover operatively connected toa generator to take a load, said prime mover being controlled by meansincluding a gate for admittingoperating fluid thereto, a motor foractuating said gate, means for controlling said motor, means responsiveto the. speed of said prime mover or governing said motor-controllingmeans, and means acting on said controlling means for preventing saidgate from opening, which com rises moving said preventing means to graually release said controlling means for, movement toward gate-openposition whereby said gate gradually opens under the control of saidspeed responsive means and said preventing means, continuing saidmovement until said prime mover reaches synchronous speed, connectingsaid. generator to said distribution system when they are in phase, and

then continuing said movement a predetermined'desired amount ator totake a load.

In testimony whereof, the signature of the inventor is afiixed hereto.ARNOLD PFAU.

to permit the gener-

